247 research outputs found
A New Approach To Estimate The Collision Probability For Automotive Applications
We revisit the computation of probability of collision in the context of
automotive collision avoidance (the estimation of a potential collision is also
referred to as conflict detection in other contexts). After reviewing existing
approaches to the definition and computation of a collision probability we
argue that the question "What is the probability of collision within the next
three seconds?" can be answered on the basis of a collision probability rate.
Using results on level crossings for vector stochastic processes we derive a
general expression for the upper bound of the distribution of the collision
probability rate. This expression is valid for arbitrary prediction models
including process noise. We demonstrate in several examples that distributions
obtained by large-scale Monte-Carlo simulations obey this bound and in many
cases approximately saturate the bound. We derive an approximation for the
distribution of the collision probability rate that can be computed on an
embedded platform. In order to efficiently sample this probability rate
distribution for determination of its characteristic shape an adaptive method
to obtain the sampling points is proposed. An upper bound of the probability of
collision is then obtained by one-dimensional numerical integration over the
time period of interest. A straightforward application of this method applies
to the collision of an extended object with a second point-like object. Using
an abstraction of the second object by salient points of its boundary we
propose an application of this method to two extended objects with arbitrary
orientation. Finally, the distribution of the collision probability rate is
identified as the distribution of the time-to-collision.Comment: Revised and restructured version, discussion of extended vehicles
expanded, section on TTC expanded, references added, other minor changes, 17
pages, 18 figure
Partial Supersymmetry Breaking from Five Dimensions
Theories of partial supersymmetry breaking N=2 -> N=1 in four dimensions are
derived by coupling the N=2 massless gravitino multiplet to N=2 supergravity in
five dimensions and performing a generalized dimensional reduction on S^1/Z_2
with the Scherk-Schwarz mechanism. These theories agree with results that were
previously derived from four dimensions.Comment: 15 pages, Latex; introduction slightly changed, one reference adde
Effect of Positive Role Model on Young Girls
Richard RosenkranzThis project focuses on the effect that an older role model or mentor can have on a younger girl regarding her attitude toward health and self-image. It looks at attitudes toward exercise, eating habits, self-esteem, and various other health topics. The data was collected through Wildcat Wellness Coaching, and the subjects were young females generally between the ages of 8 and 12. Some of the girls were exposed to Wildcat Wellness Coaching that taught them how to prepare healthy snacks and make exercising more fun. The other girls were exposed to Wildcat Wellness Coaching that taught them about important health topics that may affect them in the future. This program allowed them to meet with a coach weekly for about an hour. Each semester the participants were different and their progress was monitored from start to finish. Results showed a change in attitude of the girls who participated in one of the interventions, but not in the other
BRD4: a general regulator of transcription elongation
Transcription elongation by RNA polymerase II (Pol II) has emerged as a regulatory hub in gene expression. A key control point occurs during early transcription elongation when Pol II pauses in the promoter-proximal region at the majority of genes in mammalian cells and at a large set of genes in Drosophila. An increasing number of trans-acting factors have been linked to promoter-proximal pausing. Some factors help to establish the pause, whereas others are required for the release of Pol II into productive elongation. A dysfunction of this elongation control point leads to aberrant gene expression and can contribute to disease development. The BET bromodomain protein BRD4 has been implicated in elongation control. However, only recently direct BRD4-specific functions in Pol II transcription elongation have been uncovered. This mainly became possible with technological advances that allow selective and rapid ablation of BRD4 in cells along with the availability of approaches that capture the immediate consequences on nascent transcription. This review sheds light on the experimental breakthroughs that led to the emerging view of BRD4 as a general regulator of transcription elongation
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